The present disclosure relates generally to an exhaust system, and particularly to a particulate filter for an exhaust system.
Automotive exhaust systems for diesel and other internal combustion engines typically include an exhaust subsystem that limits the mass of particulate matter emitted with the exhaust gases. In diesel engine systems, this matter typically includes both carbonaceous components and metallic components. Present filtering methods to trap the exhaust particulates include both surface filtration and depth filtration approaches. Surface filtration relies on interception as the mechanism for particulate filtration, while depth filtration relies on impaction as the main mechanism for particulate filtration. With surface filtration systems, particulate deposits tend to block the flow path and lead to high trapping efficiency and an increase in pressure drop over time. With depth filtration systems, particulate deposits do not block the flow path, which leads to low trapping efficiency and limited change in pressure drop over time. In view of present particulate filter arrangements, it is desirable to have a more advanced particulate filter that can operate in limited space, have sufficient trapping efficiency, and can operate with limited change in its pressure drop characteristics over time.
In one embodiment, a particulate filter for an exhaust system having an exhaust flow and a nominal flow area includes a housing and a plurality of plates arranged parallel to each other within the housing, each plate having a plurality of orifices and a plurality of micropockets configured to trap exhaust particulates.
In another embodiment, a particulate filter for an exhaust system having an exhaust flow and a nominal flow area includes a housing and a plurality of plates, each plate having a plurality of orifices and a plurality of micropockets arranged within the housing and configured to trap exhaust particulates. The plates are arranged parallel to each other as plate pairs and have their micropockets facing the exhaust flow. The plates have gaps between them that decrease in size in the direction of the exhaust flow. The orifices of each plate are in line with the micropockets of an adjacent plate, each orifice being surrounded by a funnel shaped surface with the bottom of the funnel facing the exhaust flow. The total flow through area of the orifices of each plate is equal to or greater than the nominal flow area of the exhaust system.
In a further embodiment, a method for filtering particulates of an exhaust flow of an exhaust system includes receiving the exhaust flow at one end of a particulate filter, impinging the exhaust flow on the plates, collecting a portion of the particulates at micropockets on the plates, passing a portion of the exhaust flow through orifices on the plates toward a subsequent plate, repeating the impinging, collecting, and passing processes for all plates, and discharging the exhaust flow at an opposite end of the particulate filter. The plates are arranged perpendicular to the exhaust flow and have gaps between them. The orifices of each plate are in line with the micropockets of a subsequent plate.